Tuning electrical and thermoelectric properties of freestanding graphene oxide papers by carbon nanotubes and heat treatment

Electrical conductivity and Seebeck coefficient of freestanding paper of graphene oxide (GO) and GO reduced by heat treatment at 180 degrees C (rGO) are tuned by addition of carbon nanotubes (CNT). The electrical conductivity of rGO with 50% of CNT is raised to similar to 2940 S/m from similar to 613 S/m for pure rGO or similar to 34 S/m for GO with 50% of CNT without reduction. Moreover, Seebeck coefficient of rGO increases with addition of CNT from -7.04 mu V/K for pure rGO to -20.82 mu V/K for rGO with 50% of CNT, presenting n-type conductivity. As result, calculated power factor PF is enhanced with increasing CNT concentration and the highest PF similar to 1.28 mu W/(K(2)m) is obtained for rGO with 50% of CNT. (C) 2018 Elsevier B.V. All rights reserved.